The invention relates to a restraint system for vehicle occupants with a gas cushion and a gas generator that fills the gas cushion and equipped with a solid-matter propellent charge as well as an electrically activated ignition device designed as a laser and provided in order to ignite the solid-matter propellent charge, as known from the generic JP 62-178 457 (A) on which it is based.
The generic JP 62-178 457 (A) on which the present invention is based relates to a restraint system for vehicle occupants with a gas cushion and a gas generator that fills the gas cushion. The propellent charge of the gas generator is ignited by an ignition charge. An ignition charge situated in the gas generator in an ignition chamber is activated by a beam aimed directly onto the ignition charge from a laser situated outside of the generator and where if necessary the laser beam is released through an apertured partition. When applied, i.e. the system has been activated but the laser beam does not yet ignite the propellent charge, the spring-loaded apertured partition held in this position by a latching arrangement masks off the laser beam from the ignition charge. However, in a design of this kind numerous components are needed. The total number of components required up to ignition of the propellent charge results in a long transmission chain which means that the response time between the detection of the event (accident) and the inflation of the gas cushion is very long. The number of components also has the disadvantage that the greater the number the greater the probability of a component failing and hence the complete system too. Consequently, elaborate testing of the components is necessary.
From U.S. Pat. No. 5,010,822, the use of transmitting, reflecting and focussing components is known for guiding the beam from a laser that ignites a pyrotechnical system. By including these components, the steel of the laser situated outside of the chamber of the pyrotechnical system need not be joined to the ignition chamber along a straight line. In individual cases, this can facilitate installation in limited spaces. Furthermore, it is easier to blank off the laser in the activated quiescent state because only one of these components need be removed from the course of the beam or be modified.
From DE 42 11 672 A1, a safety belt for vehicle seats is known that is inflated like a hose in the event of an accident. The volume of gas required for inflation is generated by burning a propellent charge that is distributed uniformly along the length of the safety belt and where the propellent charge is ignited by an optical ignition pulse. To ensure that the propellent charge burns down approximately simultaneously along the length of the belt, the optical ignition pulse is split up and injected into the propellent charge at several points along the belt at once.